Duality
Usually we think of our experience in terms of the duality we
have developed as the experiencer and the experienced, the perceiver
and the perceived. In terms of the example of fear, we would say,
“There is fear and there is me perceiving the fear.”
We think fear exists someplace on its own, and a perceiver is
someplace else, looking and thinking, “Oh look, there is
fear.” This is the familiar and assumed position that we
are in some separate place of observation viewing the world and
our experience. But when you experience fear, are you the perceiver
separate from the fear? Remember, we are speaking now about the
immediate level of direct perception. Can you ever separate in
your experience the perception of the fear from the fear itself?
It is not possible. The perception of the fear is the same as
the experience of the fear, which is the same as the presence
of the fear. It’s as simple as that. The perceiver and the
perceived actually exist together as the experience. If we set
aside the duality of the perceiver and the perceived, then what
is actually there is consciousness aware of itself as fear. (Spacecruiser
Inquiry, pg 79)

Ego by its very nature assumes duality: the belief that who I
am is ultimately separate and discrete, and that all other manifestations
are also separate and discrete. This results in divisions in our
minds between ultimate truth and the world, spirit and matter,
Absolute Truth and relative truth, God and the universe, God and
myself, you and I, ego and essence. This belief in division as
ultimate is a conviction so deeply ingrained in the soul that
it is one of the last things we can ever contemplate confronting,
let alone releasing. (Facets of Unity, pg 92)

As the soul develops as an individual with character and identity,
with the normal emotional and mental capacities, she slowly dissociates
from her essential ground. A duality emerges between soul and
essence that becomes bedrock reality, a duality that naturally
and spontaneously separates the original unity of Reality. Soul,
originally coemergent with her true nature, turns into a duality
of self and spirit, and Reality becomes self, God/Being/spirit
and world, three separate entities. The soul becomes self, an
ego-self, that may or may not believe it has spirit, soul or true
nature. (Inner Journey Home, pg 154)

Perception and duality
Physical reality is made up of objects which can be discriminated.
If you perceive the world exclusively through the physical senses
you perceive only discrete objects, such as people, trees, animals,
rocks, clouds, oceans, earth. If you experience this level only,
which is the basis of the egoic perspective, the universe that
you see is dualistic. But if your perception is unobscured by
your beliefs, your inner perception becomes unblocked, and the
universe looks quite different. If your perceptual capacities
are clear, you recognize that other dimensions exist in addition
to physical reality, such as love, Beingness, and awareness. At
this level of perception, you see that there is only one existence,
one homogeneous medium. This medium encompasses physical reality,
which is one particularization of it. Objects are seen as objects,
but they are not discrete -- more like waves on the surface of
an ocean, lacking existence without the whole the ocean. So differentiation
exists, but not ultimate divisions. (Facets of Unity, pg 86)